The present invention relates generally to computer systems and methods, and more particularly, to a method that may be used to store basic input output system (BIOS) modules of a computer in a protected area, transfer the BIOS modules to memory, and execute the BIOS modules to configure the computer.
A BIOS, or basic input output system, refers to a firmware program that is typically stored in nonvolatile memory (flash memory), and which brings up (initializes) a computer system when it is powered on. In conventional computer systems, the BIOS is typically loaded as a single block of code into random access memory (RAM) where it is accessed by the CPU of the computer system to operate the system.
Prior art hard disk drives are capable of safely storing firmware (BIOS) in a protected area on spinning media in a tightly integrated system. A tightly integrated system is one where components used for basic operation of the hard drive are interdependent. When the hard drive is a component of a larger system, typically no other firmware components can be safely stored on the hard drive. The protected area is referred to as a vendor protected area. The vendor protected area is typically reserved for firmware of the hard disk drive manufacturer. In general, a fixed area of less than one megabyte of hard disk space is reserved for the vendor protected area.
With regard to prior art specifically related to the present invention, U.S. Pat. No. 5,835,760 issued Nov. 10, 1998, entitled xe2x80x9cMethod and arrangement for providing BIOS to a host computerxe2x80x9d, discloses operation of a computer system having a host computer with system RAM. The host computer uses a BIOS to control the operation of the computer system, and requires the host computer to obtain the BIOS and store it in the system RAM. A first portion of the BIOS (initialization code) is stored in a read only memory (ROM) which is not a flash memory, and a second portion of the BIOS is stored in a protected area of a mass memory storage peripheral computer device (hard disk) rather than in ROM. It is stated that the second portion of the BIOS may be expansion BIOS associated with a particular peripheral computer device or system BIOS associated with the host computer.
In operation, as is stated in U.S. Pat. No. 5,835,760, the first portion of the BIOS (initialization code) is read out of the ROM into the host computer. The host computer executes instructions contained in the first portion of the BIOS and reads the second portion of the BIOS (i.e., the entire BIOS) from the protected area of the hard disk drive into the system RAM. The second portion of the BIOS is executed to operate peripheral computer devices or the computer.
U.S. Pat. No. 5,835,760 does not disclose or suggest the use of a flash memory or nonvolatile memory, and does not disclose or suggest storing any portion of the BIOS in a flash memory. Furthermore, U.S. Pat. No. 5,835,760 does not disclose or suggest selectively transferring modules of the BIOS into RAM, only the entire BIOS associated with the peripheral computer devices or the computer.
It is an objective of the present invention to provide for improved methods that may be used to store basic input output system (BIOS) modules of a computer in a protected area, transfer the BIOS modules to memory, and execute the BIOS modules to configure the computer. The present invention is an improvement over the teachings of U.S. Pat. No. 5,835,760.
To accomplish the above and other objectives, the present invention provides for methods that process basic input output system (BIOS) modules of a computer to initialize a computer. The methods store basic input output system (BIOS) modules of the computer in a protected area, transfer the BIOS modules to system memory, and execute the BIOS modules to configure the computer. The computer includes a system memory, a central processing unit (CPU), a computer bus, a critical nonvolatile storage device and optional secondary nonvolatile storage device(s). Selected BIOS modules required for operation of the computer are transferred from the critical nonvolatile storage device, and optionally the protected area of the secondary nonvolatile storage device, to system memory, and are executed to initialize the computer.
The critical nonvolatile storage device may be flash memory, read only memory (ROM), programmable read only memory (PROM), erasable programmable read only memory (EPROM), or electrically erasable programmable read only memory (EEPROM), or other device or technology that the CPU may use to execute an initial set of instructions. The secondary nonvolatile storage device may be a hard disk drive, a compact disk (CD) drive, a digital video disk (DVD) drive, a floppy disk drive, a Zip drive, a SuperDisk drive, a Magneto-Optical disk drive, a Jazz drive, a high density floppy disk (HiFD) drive, flash memory, read only memory (ROM), programmable read only memory (PROM), erasable programmable read only memory (EPROM), or electrically erasable programmable read only memory (EEPROM), or any other device capable of preserving data in the event of a power-off condition.
The basic input output system (BIOS) is firmware that is typically stored in solid state non-volatile memory. The present invention allows multiple CPUs and system devices to be initialized from firmware (BIOS) stored on non-solid state system resources. The present invention allows the system to safely store and reliably retrieve firmware from a non-solid state device.
In one embodiment of the present invention, a minimal amount of BIOS initialization code is stored in a first portion of the critical nonvolatile storage device. The minimal initialization code is operative to initialize the CPU and the system memory. Additional BIOS modules are stored in the critical nonvolatile storage device or a protected area of the secondary nonvolatile storage device. A dispatch manager is stored in a second portion of the critical nonvolatile storage device. The dispatch manager is operative to selectively load and iteratively execute a predetermined number of tasks relating to complete initialization of the computer.
After the computer is turned on, the minimal initialization code is executed to initialize the CPU and the system memory. The dispatch manager is copied from the critical nonvolatile storage device to the system memory. The dispatch manager sequentially executes the predetermined number of tasks to initialize the computer.
The plurality of BIOS modules that are operative to control operation of the computer may be stored in a protected area of the critical nonvolatile storage device. The dispatch manager executes to sequentially copy selected BIOS modules identified in its list of tasks to execute. These BIOS modules are copied from the protected area of the secondary nonvolatile storage device to the system memory and are then executed.
The dispatch manager may also operate to determine which BIOS modules are required for operation of the computer and determine if a required BIOS module is stored in the system memory. If the required BIOS module is stored in memory, then the dispatch manager executes the stored BIOS module. However, if the required BIOS module is not in memory, then the dispatch manager copies the required BIOS module from the secondary nonvolatile storage device to the system memory and then executes the copied BIOS module. The dispatch manager repeats this procedure until all required BIOS modules are copied and executed. Once all of the required BIOS modules are copied into the system memory and executed, the operating system of the computer is launched and normal computer operation ensues.
The present invention thus allows system firmware (BIOS) to be stored on nonvolatile storage devices that are loosely integrated with the system. The basis of this operation is the ability to create a protected area on the nonvolatile storage device. In a hard disk environment, this protected area is distinct from the vendor-protected area discussed previously. This protected area can be accessed by the system firmware (the minimal initialization BIOS code), and BIOS modules required for the system are read from the protected area into system memory. The nonvolatile storage device denies all other access to the protected area allocated to the BIOS.
Heretofore, no computer or BIOS manufacturer has stored initialization BIOS in a first portion of a nonvolatile storage device which is executed to load a dispatch manager from a second portion of the nonvolatile storage device into system memory which is subsequently used to copy individual BIOS modules stored in a protected area and execute the copied individual BIOS modules to initialize the computer.
As was mentioned above, conventional hard disk drives include a hidden vendor-protected area where hard drive firmware is stored. However, in another embodiment of the present invention, the secondary nonvolatile storage device, and in particular a hard disk drive, is configured to have a second hidden protected area where the BIOS modules are stored. This BIOS module storage area is distinct from the vendor-protected area normally found on hard disk drives.